Using GarageBand
Download GarageBand from the App Store if you haven't already1
Open GarageBand and create a new audio recording
Choose your audio source:
Use an audio file stored on your device
Select a song from your Apple Music library (must be downloaded)1
Editing Your Ringtone
Select the section of the song you want to use
Ringtones can be up to 30 seconds long
Drag the audio file to the left in the Tracks view
Trim the audio by dragging the edges of the file15
Exporting the Ringtone
Tap the Navigation button and go to My Songs
Select the song and tap Ringtone
Name your ringtone
Export the ringtone
Setting the Ringtone
After exporting, you can:
Set it as your standard ringtone
Assign it to a specific contact
Use it as a text tone1
Alternative Methods
If you prefer using a computer:
Use iTunes to convert a song to a ringtone
Change the file extension from .m4a to .m4r
Sync the ringtone to your iPhone2
Pro Tips
Ensure the song is less than 30 seconds
Make sure you have the rights to use the audio
Experiment with different sections of the song https://click4r.com/posts/g/19692957/to-make-a-video-sound-your-ringtone-you-can-follow-these-steps-using  https://chestnut-apple-nrqhn2.mystrikingly.com/blog/several-online-tools-can-convert-text-to-speech-for-creating-ringtones  https://rentry.co/b3s37kkk